Pump



Dec. 13, 1966 W. G, MCKENZIE 3,291,054

PUMP

Filed Jan. 8, 1965 fax/V506'.

United States Patent O Claims. (Cl. 103-40) This invention relates generally to fluid pumping means and, more particularly, to a pumping device for maintaining a predetermined fluid pressure within an associated fluid metering system.

It is a general object of the present invention to provide a fluid pumping device which pumps fluid from an associated fluid reservoir to a fluid metering system and maintains the fluid pressure within the system at a predetermined level, the device also serving to communicate any excess fluid back to the reservoir.

It is another object of the present invention to provide a fluid pumping device of the above character which has very few moving components and therefore has a a long service life.

It is still another object of the present invention to provide a fluid pumping device of the above character that is simple in construction and operation and which is therefore economical to produce.

It is yet another object of the present invention to provide a fluid pumping device of the above character which cycles automatically.

It is still a further object of the present invention to provide a fluid pumping device of the above character which comprises means for controlling the cyclic rate of operation thereof.

In accordance with the principles of the present invention, the foregoing and other related objects and advantages are attained through the provision of a novel pumping device which includes a thermal actuated piston assembly and a timing valve assembly which serves to control the cyclic rate of operation of the piston assembly. The pumping device of the present inventionalso includes a combination check valve and relief valve mechanism which is preloaded such that when a preselected fluid pressure level is achieved through operation of the device, any excess or surplus fluid will be automatically communicated back to the associated fluid reservoir.

A more complete understanding of the present invention and other objects and features thereof will be obtained from the following detailed description taken in conjunction with the accompanying drawing, wherein:

FIGURE 1 is a longitudinal cross-sectional view of the pumping device embodying the present invention;

FIGURE 2 is a top elevational view of the pumping device illustrated in FIGURE 1; and

FIGURE 3 is an end elevational view of the pumping device illustrated in FIGURE 1.

Referring now to FIGURE l of the drawing, a fluid pumping device 10, in accordance with a preferred embodiment of the present invention, is shown, as comprising a generally square-shaped'piston housing 12 which `is formedwith a central annular bore that defines a pumping chamber 14. The housing 12 is rigidly secured, as by a plurality of suitable machine screws 16, between a pair of spaced parallel leg sections 18 and 20 of a generally U-shaped mounting bracket 22. The bracket 22 comprises an end section 24 which extends between the left ends of the leg sections 18 and 20 and supports a thermal energized drive motor 26 which serves to actuate the pumping devicevll), as will later be described.

Reciprocally mounted within the pumping chamber 14 is a generally cup-shaped piston member 28 which is formed with a radially outwardly extending flange section 30 at its open (left) end. A suitable O-ring sealing ICC member 32 is compressed between an annular recess A34 formed around the inner periphery of the chamber 14, and the outer periphery of the piston member 28, which sealing member 32 serves to prevent fluid leakage between the left end of the chamber 14 and the outer periphery of the piston 28. A helical return spring 36 extends around the outer periphery of the left end of the housing 12 and abuts at its right end against an annular shoulder 38 defined by a medial portion of the housing 12. The opposite (left) end of the return spring 36 abuts against the outwardly projecting flange section 30 of the piston member 28, whereby the spring 36 functions to resiliently urge the piston member 2S toward the right end of the motor 26.

Fluid is selectively communicated into the pumping chamber 14 by means lof a combination check valve and relief valve assembly, generally designated 4t) and comprising a hexagonal-shaped valve housing 42, as seen in FIGURES l and 3. The housing 42 has a mounting section 44 which is threadedly mounted within a fluid inlet passage 46 that is formed in the right end of the piston housing 12. The valve housing 42 and the mounting section 44 thereof are hollow and are thus communicable with the interior of the fluid inlet passage 46. A plug or cover member 48, which is formed with a central outwardly projecting nipple section 50 and a central bore 52, is threaded within said closes the outer (right) end of the valve housing 42, the nipple section 50 being inserted within one end of a fluid inlet conduit 54 which serves to communicate fluid to the valve assembly 40 from an associated fluid source or reservoir. Disposed within the interior of the valve housing 42 is a cup-shaped valve member 56 which is formed with a radially outwardly projecting shoulder section 58 at one end and a central discharge orifice 60 at the opposite end. The shoulder section 58 is resiliently urged into engagement with an O-ring sealing member 62 disposed at the left end of the valve housing 42 by a helical valve spring 64 which extends around the outer periphery of the valve member 56 and engages the right side of the shoulder section 58 and the left side of the cover member 48, as seen in FIGURE l. A spherical check valve 66 is disposed within the interior of the valve member 56 and is resiliently engaged with an O-ring sealing member 68 disposed at the right end of the member 56 by a coil spring 70 that extends coaxially within the member 56. It will be seen that when the fluid pressure within the chamber 14 reaches a predetermined level, the valve member 56 will pop against the resistance of the spring 64, whereby the fluid within the chamber 14 will flow through the interior of the valve housing 42 and the conduit 54 to the fluid reservoir, as will later be described.

Fluid is communicated out of the chamber 14 through a fluid outlet passage 72 that is formed in the right end of the housing member 12 directly above the fluid inlet passage 46. A fluid outlet fitting 74 is threaded Within the right end of the passage 72 and communicates the passage 72 with a fluid outlet conduit 76 which is adapted to communicate fluid from the pumping device 10 to an associated fluid metering or a dispensing mechanism (not shown).

As best seen in FIGURE l, the thermal motor 26 comprises an elongated cylindrical housing 78 which is secured to the end section 24 of the mounting bracket 22 by a retaining plate 80 which is rigidly secured to the left end of the housing 73 and is welded or similarly attached to the left side of the section 24. The motor 26 is preferably of the wax pellet type and includes a suitable electric heating element (not shown) which is adapted to be energized by connecting a suitable source of electric current with a pair of lead lines 82 which are communicable with the heating element. Upon energization of the heating element, a wax pellet that is disposed within the housing 78 adjacent the element expands a predetermined amount, thereby forcing a piston rod 84, which projects from the right end of the housing 78, toward the right to elfect actuation of the pumping device 10.

Secured to the top of the section 20 of the mounting bracket 22 by a suitable machine screw 86 is a Z-shaped actuating switch support bracket 88 upon which an actuating switch 90 is rigidly attached by means of a pair of screws 92 and 94. The switch 90, which is of a conventional toggle type and connected with the aforementioned source of electric current used to energize the thermal motor 26, comprises a deenergizing section 96 and a reenergizing section 98 that project from the left and right sides thereof, respectively. The motor 26 is adapted to be deenergized upon engagement of the section 96 with a tripping bar 100 which is formed with a sleeve section 102 at its lower end within which the left end of a horizontally extending drive pin 104 is secured by means of a conventional set screw 106. The opposite (right) end of the drive rod 104 extends through a central opening 107 in the switch supporting bracket 88 and is rigidly secured to a bracket 108 which is connected at its lower end to the flange section 30 of the piston member 28 and extends upwardly through a rectangular opening 110 formed in the section 20 of the mounting bracket 22, as best seen in FIGURE 2. It will be seen from the foregoing that as the piston member 28 moves to the right upon energization of the motor 26, the bracket 108 and drive pin 104 will bias the tripping bar 100 into engagement with the deenergizing section 96 of the switch 90, thereby ellecting deenergization of the motor 26. The reset section 98 of the switch 90 is adapted to be engaged by a tripping bracket 112 which is rigidly secured to the left end of a cylindrical rod or shaft 114 that abuts against the right side of the bracket 108 such that the rod 114 will move to the right along with the drive rod 104 and bracket 108 upon actuation of the motor 26. Movement of the bracket 112 and rod 114 toward the switch 90 is controlled through a cyclic timing assembly, generally designated 116, as will hereinafter be described.

The assembly 116 comprises a rectangular-shaped housing 118 that is formed with an annular bore or chamber 120 and which is secured to the top of the section 20 of the bracket 22 by a pair of screws 122 and 124. Reciprocally mounted within the bore 120 is a timing piston 126 that is rigidly secured to the right end of the rod 114 which extends through an opening 128 formed in the left end of the housing 118. A suitable O-ring sealing member 130 is provided in an annular recess 132 that is formed around the bore 128. Disposed around the outer periphery of the piston member 126 is a U-cup annular packing member 134 which is constructed of a resilient and deformable material such as a lluid resistant synthetic rubber or the like. The piston member 126 is formed with an axially extending bore 136 which is communicable at its left end with a bore 138 that extends diametrical-ly through the piston member 126. The bore 136 is formed with a tapered medial section 140 and is communicable With a bore 142 which extends radially within the piston member 126 immediately to the right of the tapered section 140. A needle valve member 144 is threadably mounted within the right end of the piston member 126 and is adapted to be selectively adjusted therein such that its left end is engageable with the tapered section 140 of the bore 136 to control the llow of fluid between the bores 138 and 142.

The piston member 126 is resiliently urged toward the left end of the housing 118 by means of a helical timing spring 146 which extends coaxiallywithin the bore 120 and is engageable at its left end with an outwardly projecting shoulder section 148 formed on the piston member 126, and is engageable at its right end with a cup-shaped plug or closure member 150 which is threaded within and closes the right end of the bore 120. An O-ring sealing member 152 is interposed between the right end of the housing'118 and the closure member 150. The housing 118 contains a predetermined quantity of lluid which, upon actuation of a motor 26 and movement of the rod 114 and piston member 126 to the right, flows from the right end of the bore 120, around the outer periphery of the packing member 134, to the left end of the bore 120. When the drive pin 104 moves to the left due to the action of the return spring 36 on the piston 28, the timing spring 146 will force the piston member 126 and rod 114 toward the left end of the housing 118, whereby the fluid between the left end of the housing 118 and the piston member 126 is forced through the bores 138, 136, and 142 to the right end of the bore 120. It will be seen that the rate at which the fluid flows between the bores 136 and 142 is controlled by the adjustment of the needle valve 144 within the piston member 126, and hence the time required for the piston member 126 to traverse from the right end of the housing 118 to the left end thereof and consequently the time interval between deenergization of the motor 26 and engagement of the bracket 112 with the switch 90 effecting reenergization of the motor 26, is controlled by the relative adjustment of the needle valve 144.

To facilitate correlating each of the hereinbefore described components of the pumping device 10 Of the present invention, the cyclic operation of this device will now be given. Assuming that the lead lines 82 are connected to a suitable source of electric current, and that the fluid inlet and outlet conduits 54 and 76 are connected to an appropriate source of fluid and to an associated fluid metering or dispensing mechanism, respectively, the operational cycle of the pumping device 10 commences upon energization of the thermal motor 26, as by actuating an external switching mechanism (not shown) to complete the electrical circuit to the motor 26. Upon energization of the motor 26, the piston rod 84 will be biased outwardly or away from the right end of the motor housing 78, thereby urging the piston member 28 toward the right end of the pumping chamber 14. As the piston member 24 is thus moved, the fluid within the chamber 14 will be forced through the lluid outlet passage 72 and fluid outlet conduit 76, the reason for this being that the check valve 66 prevents fluid within the chamber 14 from being forced back into the fluid inlet conduit 54. When the fluid pressure within the associated iluid metering or dispensing device reaches a predetermined level, the valve member 56 will pop or move to the right against the resistance of the spring 64, thereby unseating the shoulder section 58 of the member 56 from the sealing member 62 and permitting the excess or surplus lluid within the pumping chamber 14 to flow back through the valve assembly 40 and the conduit 54 to the fluid reservoir.

The forward movement of the piston member 28 is terminated when the tripping bar 100, which is secured to the piston member 28 by means of the drive pin 104 and bracket 108, engages the deenergizing section 96 of the switch to effect deenergization of the motor 26, at which time the return spring 36 biases the piston member 28, bracket 108, pin 104 and bar 100 toward the left. It will be seen that as the piston member 28 moves to the right within the pumping chamber 14 during the discharge portion of the operational cycle, the bracket 108 biases the rod 114 and piston member 126 toward the right end of the timing assembly housing 118, whereby the fluid within the bore flows around the outer periphery of the packing member 134 to the left end of the housing 118. After deenergization of the motor 26 and movement of the piston member 28 and bracket 108 away from the rod 114 through action of the return spring 36, the spring 146 forces the piston member 126 toward the left end of the bore 120, causing the lluid in the housing 118 to flow through the bores 138, 136 and 142, as above described, the speed at which the piston member 126 and rod 1M are biased toward the left being'controlled by the adjustment of the needle valve 4M4 Within the piston member 126. When the piston member 126 and rod 1M have moved a predetermined distance, the bracket 112 which is secured to the left end of the rod 114 engages the reenergizing section 98 of the switch 90, thereby energizing the motor 26 to effect the next successive operational cycle of the pumping device 10, as hereinabove described.

It will be seen from the aforegoing construction that the pumping device of the present invention provides an extremely simple and compact unit which, upon being initially energized, will cycle automatically to maintain a predetermined fluid pressure within an associated huid metering or dispensing mechanism. It will also be seen that the pumping device 10 includes means for controlling the cyclic rate of the operation thereof and for controlling the ow of excess uid back to an associated fluid reservoir when a predetermined fluid pressure is attained within the fluid metering mechanism. The device It) will find particular application when used with a fluid metering device of the type employed in supplying lubricating fluids to a series of bearing surfaces in a production machine or the like. It will be apparent, of course, that the pumping device l0 of the present invention is not limited to such use and may be incorporated in any of a number of iuid systems requiring that a minimum uid pressure level be maintained therewithin.

While it will be apparent that the preferred embodiment therein illustrated is well calculated to fulll the objects above stated, it will be appreciated that the pumping device l0 of the present invention is susceptible to modification, variation and change without departing from t'he proper scope or fair meaning of the subjoined claims.

What is claimed is:

ll. In a uid pumping device,

a housing defining a pumping chamber,

piston means reciprocable within said chamber,

electrically heated expandable wax thermal motor means for moving said piston means within said chamber,

electrical switch means operated by said piston means for deenergizing said motor means, and

means for reenergizing said motor means.

2. The invention as set forth in claim i. wherein said means for reenergizing said motor means comprises valve means movable in response to movement of said piston means.

3. The invention as set forth in claim l which includes valve means to selectively communicate iiuid to said chamber and for relieving the fluid pressure within said chamber when said fluid pressure reaches a predetermined level.

4;. In a fluid pumping device,

a housing defining a pumping chamber,

piston means reciprocable within said chamber,

i motor means for moving said piston means within said chamber,

means for deenergizing said motor means, and

timing means including fluid valve means for reenergizing said motor means, and a combination check and relief valve means for selectively controlling the flow of uid to and from said chamber.

5. In a fluid pumping device,

a housing defining a pumping chamber,

fluid inlet and outlet passages formed in said housing and communicating fluid to and from said chamber,

a uid relief valve in one of said passages,

said relief valve comprising a movable valve member and spring means yieldably seating said member,

a check valve in one of said passages and comprising a valve member and spring means yieldably seating said member,

piston means reciprocable within said chamber,

motor means for moving said piston means within said chamber,

means for deenergizing said motor means, and

timing means including valve means for reenergizing said motor means.

6. The invention as set forth in claim 5 wherein said relief valve and said check valve are arranged in a single valve housing communicable within said fluid inlet passage.

7. The invention as set forth in claim 5 wherein said timing means comprises a timer housing, a plunger recip rocable within said timer housing, yieldable packing means arranged between said plunger and said housing, and valve means adjustably mounted on said plunger, said plunger having an axial bore within which said valve means is disposed, said plunger also having iirst and second radially extending bores communicating with said axial bore on the opposite sides of said valve means, whereby adjustment of said valve means within said axial bore selectively controls the ow of fluid between said first and second radially extending bores.

8. In a tiuid pumping device,

a mounting structure,

a housing secured to said structure and defining an annular pumping chamber.

huid inlet and outlet passages formed in said housing and communicating fluid to and from said chamber,

a fluid relief valve in said inlet passage,

a iiuid check valve in said inlet passage,

a piston member reciprocable within said chamber,

motor means for biasing said piston in one direction Within said chamber,

a return spring for biasing said piston in the opposite direction within said chamber,

a switch for controlling energization of said motor means,

means including means movable with said piston for deactuating said switch,

a timer housing on said structure,

a plunger reciprocable within said timer housing,

valve means for controlling the movement of said plunger within said timer housing, and

means connected to said plunger and movable with said piston for actuating said switch.

9. The invention as set forth in claim 8 wherein said motor comprises a heating element and an expandable wax pellet.

l0. In a fluid pumping device, a housing defining a pumping chamber, piston means reciprocable within said chamber, motor means for moving said piston means within said chamber, means for deenergizing said motor means, timing means including uid valve means for reenergizing said motor means, and timing means comprising a timer housing, a plunger reciprocable within said timer housing and valve means for controlling the movement of said plunger within said timer housing.

References Cited by the Examiner UNITED STATES PATENTS 2,925,786 2/1960 Hill 230-230 X 2,976,675 3/1961 Bonner 60-25 3,012,513 12/1961 Knox 10S-52 ROBERT M. WALKER, Primary Examiner. 

1. IN A FLUID PUMPING DEVICE, A HOUSING DEFINING A PUMPING CHAMBER, PISTON MEANS RECIPROCABLE WITHIN SAID CHAMBER, ELECTRICALLY HEATED EXPANDABLE WAX THERMAL MOTOR MEANS FOR MOVING SAID PISTON MEANS WITHIN SAID CHAMBER, ELECTRICAL SWITCH MEANS OPERATED BY SAID PISTON MEANS FOR DEENERGIZING SAID MOTOR MEANS, AND MEANS FOR REENERGIZING SAID MOTOR MEANS. 